Method of enhancing detection of defects on a surface

ABSTRACT

A method that may be applied to imaging and identifying defects and contamination on the surface of an integrated circuit is described. An energetic beam, such as an electron beam, may be directed at a selected IC location having a layer of a solid, fluid, or gaseous reactive material formed over the surface. The energetic beam disassociates the reactive material in the region into chemical radicals that either chemically etch the surface preferentially, or deposit a thin layer of a conductive material over the local area around the energetic beam. The surface may be examined as various layers are selectively etched to decorate defects and/or as various layers are locally deposited in the area around the energetic beam. SEM imaging and other analytic methods may be used to identify the problem more easily.

RELATED APPLICATION

This application is a Divisional of U.S. application Ser. No.11/483,800, filed Jul. 10, 2006, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

This application relates generally to semiconductor devices and devicetesting and, more particularly, to detection and analysis of defects anderrors associated with electrical function failures and long termreliability failures in integrated circuit (IC) devices, includingindividual die, packaged die or die still on semiconductor wafers, suchas memory devices, logic devices and microprocessors.

BACKGROUND

The semiconductor device industry has a market driven need to reduce ICdevice failures at electrical test, and to improve the operationallifetimes of IC devices. Reduced device failures may result in increasedIC fabrication yield and improved device operational lifetime. IncreasedIC fabrication yields may result in decreased IC prices, and improvedmarket share.

One method to reduce the number of device failures is to analyze faileddevices and determine the cause of the failure. The failures may be whatare known as field failures that occur at customer sites, or they mayoccur in products that have been sold to consumers. The failures may befound during wafer level testing at the end of wafer fabrication, or intesting after a supposedly good IC die is placed in a package, or intesting after a supposedly good IC package is placed in a printedcircuit board (PCB).

It is known to examine failed devices by means of electrical testing,optical microscopes, transmitting electron microscopes (TEM), scanningelectron microscopes (SEM), and other well known methods. If, forexample, a particle is found that produces a short between twoconductive lines in a signal layer, then action may be taken at thefabrication site to reduce particle levels, and thus increasefabrication yield. This method may be used in cases where the failure,such as the illustrative particle just discussed, is at, or near, thesurface of the sample, since the failure may not be otherwise visible inan optical or an electron microscope.

However, as the semiconductor device industry has increased the level ofintegration of their devices and packed more capability on ever smallersemiconductor chips, the critical dimension, or size, of eachtransistor, each conductive line, and the spacing between lines hasdecreased. As a result of the smaller lines and smaller spaces, the sizeof a defect that may result in a device failure has also decreased,which means that the same defects and particles that were not likely tocause failures in previous generations of electronic devices are nowdevice killers. The smaller defects are harder to detect and observewith the existing methods of detection and evaluation, and some methodto enlarge the defects, which may be known as decorating, or ofincreasing the defect contrast as compared with the device background isneeded to improve defect detection.

A method is needed to chemically etch a small area around a defect withhigh selectivity between the etch rates of the materials forming thedefect and the materials forming the semiconductor substrate. This wouldimprove the visual and SEM delineation, or contrast, between the defectand the substrate. In addition, or in the alternative, a layer ofconductive material needs to be deposited, either selectively ornon-selectively, on the surface of the substrate to decorate the defect,thus improving the ability to observe the defect. The ability to observethe defect during the localized etching and/or deposition, and theability to stop the etching or decorating when the best image isobtained would also be beneficial. The ability to analyze thecomposition of the materials being etched or decorated prior tobeginning the enhancement process, would improve the proper selection ofthe optimum etch mixture and conditions. With such an arrangement, thedefect sample may be imaged during the small spot localized etchingand/or deposition, and the process may continue until the desired levelof decoration or enhancement structure is obtained.

These and other aspects, embodiments, advantages, and features willbecome apparent from the following description and the referenceddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a semiconductor device in cross section;

FIG. 2 illustrates the semiconductor device of FIG. 1 in a vacuumchamber in accordance with an illustrative embodiment;

FIG. 3 illustrates the semiconductor device of FIG. 1 in anotherillustrative embodiment;

FIG. 4 is a flowchart of the method in accordance with an illustrativeembodiment;

FIG. 5 is a block diagram of an electronic device in accordance with anembodiment of the invention; and

FIG. 6 is a diagram of an electronic system having devices in accordancewith an embodiment of the invention.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific aspects and embodiments inwhich the present invention may be practiced. These embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the present invention. Other embodiments may be utilized andstructural, logical, and electrical changes may be made withoutdeparting from the scope of the present invention. The variousembodiments are not necessarily mutually exclusive, as some embodimentscan be combined with one or more other embodiments to form newembodiments.

The term “horizontal” as used in this application is defined as a planeparallel to the conventional plane or surface of a wafer or substrate,regardless of the orientation of the wafer or substrate. The term“vertical” refers to a direction perpendicular to the horizontal asdefined above. Prepositions, such as “on”, “side” (as in “sidewall”),“higher”, “lower”, “over” and “under” are defined with respect to theconventional plane or surface being on the top surface of the wafer orsubstrate, regardless of the orientation of the wafer or substrate. Thefollowing detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present disclosure is defined onlyby the appended claims, along with the full scope of equivalents towhich such claims are entitled.

The described embodiments provide a method for localized acceleratedselective chemical etching of an integrated circuit (IC) to improvecontrast between different materials on the IC surface, or to depositmaterials locally on the surface of the IC to enlarge or decoratedefects. The detection of surface defects having ever decreasingdimension may require exaggeration of the structure of the defect.Electron induced chemical etching and deposition can be used to increasethe contrast of defects, and to decorate the defects, resulting inincreased visibility of surface defects in SEM and optical micrographs.Depositing a material with more favorable imaging properties than thedefect or substrate improves imaging efficiency, and may increase thesize of the defect. As an illustrative example, it is difficult todetect small nitride flakes produced when a nitride surface isscratched, as may typically occur either by handling, vibration ortransportation. The visibility of the nitride flake may be enhanced bydepositing a thin layer of chromium on the surface of the IC, either achip or a wafer. The layer of chromium may be thinner than 2 nm, and mayhelp dissipate charge build up in a SEM image. The chromium has a higherelectron yield as compared to nitride, and increases the signal to noiseratio in a SEM image. The addition of the chromium layer to the particleincreases the particle size, while the addition of the chromium to thesubstrate has little proportional effect on the appearance of thesubstrate, thus improving the visibility of the particle in SEM and inoptical microscopes. The chromium is reflective and bright under opticalmicroscopes, particularly in what is known as black field illuminationmode, and thus improves the visibility of the particle.

Etching may also be used to enhance imaging efficiency by exaggeratingthe contours of the defect to increase contrast and visibility,especially along edges and material boundaries. In the illustrativeexample of a particle formed of a different material than the substrate,the use of an etch composition having a preferential etch rate for thesubstrate material exaggerates the surface in the vicinity of theparticle, due to the masking effect of the particle. The particle may bemore visible due to the increased area and topographical heightdifferences caused by the etching of the substrate material in theregion near the defect. This method may be particularly useful inenhancing the image of particles formed by environmental contaminationsuch as dust, or for metallic particles from handling the IC withprocessing tools.

In an embodiment, the localized chemical accelerator is an energeticbeam, such as an electron beam, and the excited material is a halogencontaining compound, forming a layer on, or immediately above, thesurface of the IC in a vacuum chamber, such as inside a scanningelectron microscope (SEM). Localized electron beam assisted chemicaletching provides a method of localized selective etching or decorationdeposition, as may be useful in IC failure analysis of defects.

In an illustrative embodiment, localized etching to increase contrastmay occur by passing a halogen containing gaseous material over thesurface of the IC chip in the vacuum chamber, and exciting the halogenatoms with an electron beam to form chemical radicals. By controllingthe vacuum pressure and the gas flow, the mean free diffusion length(and equivalently the lifetime) of the radicals may be controlled, andthe etching of the IC surface may be substantially confined to a desiredregion around the electron beam. Electrons from the primary beam,electrons scattered from the IC surface, as well as secondary electronsand ionizing radiation emitted from the IC surface may all cause theformation of the radicals by dissociating the individual molecules oratoms of the halogen containing layer. The halogen containing layer maybe adsorbed onto the surface of the IC, as may occur when using a sourcematerial such as xenon difluoride, which sublimates in a vacuum and maydeposit on the surface of the IC.

FIG. 1 illustrates a semiconductor device 100, having a substrate 102,with a series of conductive regions 104 formed in or on the substrate.The conductive regions 104 may be formed from diffused portions of thesubstrate 102, from doped polysilicon, or from various metals and metalsilicides. Above the conductors 104 is a dielectric layer 106, and agate electrode 108. The gate electrode 108, the gate dielectric 106, andthe conductive regions 104, form a typical semiconductor device, with aprotective dielectric layer 110, and signal and power interconnections112 and 114. The various conductive materials 112 and 114 may be purematerials or combinations of materials, such as copper doped aluminum,or may be formed of multiple layers, such as having titanium, ortitanium-tungsten, or titanium nitride barrier layers under theconductors 112 or 114. The conductors 112 and 114 are protected fromenvironmental problems such as scratches and ionic contamination by adielectric layer 116, and selected conductors may electrically connectto the gate electrode 108 by a contact hole 118 in the dielectric layer110.

The dielectric layer 116 is shown in the illustrated embodiment with aparticle 120 on the surface. Examples of such particles may include achipped piece of the dielectric 116 caused by a handling error such as ascratch, or may be a particle of the same composition as the dielectric116 that fell upon the device at the end of the deposition process thatformed dielectric layer 116. Other examples include metal particles fromthe machinery that handles and transports the semiconductor wafers inprocessing, and environmental contaminants. In the case where theparticle 120 is of the same basic composition as the dielectric layer116, detecting and imaging the particle may be difficult, since theparticle properties are similar to the background material. The presentmethod provides a method of either removing a small amount of thedielectric layer 116, so that the contrast between the particle 120 andthe dielectric 116 may be improved.

FIG. 2 illustrates the semiconductor device of FIG. 1 in a vacuumchamber 232, in an embodiment, a SEM, having a vacuum pump (not shownfor simplicity), an inlet 234, and an energetic beam 236, such as anelectron beam, which may be movable. The inlet 234 may be a directed gasjet as shown, or a sublimation port, a gas shower head, a bubbler, or aliquid material sprayer, such as an atomizer. The inlet 234 supplies theregion around the top surface of the sample with a material that iseither reactive, or may be made reactive, such as a halogen containingmaterial. The atoms of the halogen in this illustrative example areshown as floating “H” symbols, some of which are adsorbed onto thesurface of the sample, and some diffusing around the chamber 232.

The vacuum chamber 232 has a directed and focused energetic beam device236, which in an embodiment is a SEM beam, directed to a desiredlocation on the surface of the sample. The electron beam device 236emits electrons 238 (shown as “e⁻” symbols) which excite the halogenmolecules or atoms (H) floating in the vacuum chamber 232, or adsorbedonto the surface of the sample, and form a chemically reactive radical,denoted by “H*”. Due to the limited lifetime of the radicals, theradicals H* are limited to the area around the electron beam 236 shownby the dotted lines 240. The selected radicals H* have a much greaterchemical etch rate on the dielectric layer 216, than the halogenmolecules or atoms (H), and thus the etching of the two shown pits oneither side of the particle 120 (which represents the generally circularor annular etch region in three dimensions) occurs wherever theillustrative electron beam forms the H* radicals. In an illustrativeembodiment, the halogen compound is xenon difluoride, which formsfluorine radicals when excited by the electron beam. The fluorineradicals have a large etch rate on the top dielectric layer 216, but theareas immediately under portions of the particle 220 are not etched asrapidly due to shadowing. In such a fashion, it is possible to etch pitsin the dielectric 216 to improve the visual and SEM contrast around theparticle 120.

FIG. 3 illustrates another illustrative embodiment of the device of FIG.1, after a period of local deposition of an illustrative decorativelayer on the particle 320. In this illustrative embodiment, thepotential solution to the problem of imaging and detecting the particle320 is to decorate the particle by increasing its relative size andelectron yield by coating the particle with a conductive material suchas chromium. In this embodiment the injector 334 introduces a chromiumhalide material, indicated as CrH. The illustrative energetic beamapparatus 336 (in this embodiment an electron beam) having sufficientenergy to create chemical radicals denoted by Cr*, in a chromium halidematerial CrH, which is a gas in this embodiment that is either floatingin the vacuum in vacuum chamber 332, or adsorbed onto the surface of theIC or onto the surface of the particle 320. The energetic beam causesthe formation of a chromium metal layer on the particle 320. In anembodiment, the chromium layer is from 1-100 nanometers in thickness,and decorates the particle for easier detection and evaluation. In anembodiment, the thickness of the chromium metal is determined by SEMobservation during the metal deposition, and direct determination of thebest image quality. In other embodiments, depending upon the vaporpressure of the chromium containing material under the specific vacuumconditions, the chromium may be in the form of liquid droplets, or asolid formed on the surfaces of the particle and the substrate withinthe limits of the beam edges 240. In such a fashion, it is possible tocause chromium halide to disassociate and deposit chromium metal toimprove the imaging and detection of the particle 320.

In an embodiment, the etching shown in FIG. 2 is combined with thedeposition discussed with regard to FIG. 3, to further maximize thedefect delectability. In another embodiment, the etching and depositingmay be used to remove a layer from the IC and decorate and image adefect in a buried layer. In yet another embodiment, the chemicalradicals include a silicon containing material such as silane or TEOSand an oxygen containing material and a hole etched in the IC may befilled to repair the IC and return it to operational condition.

FIG. 4 is a flow diagram showing the method for electron inducedchemical etching for device level diagnosis of potential problems. Themethod starts at 402 with obtaining a sample, such as an IC, fordecoration or contrast etch. At 404 the sample is placed in a vacuumchamber, such as a SEM, and the chamber begins to be evacuated at 406.At 408, it is decided whether or not the chamber has been pumped to adesired vacuum pressure, which may be used to control the mean free pathof the radicals generated by the electron beam. If the desired pressureis not yet obtained, the method returns to 406. When the proper vacuumlevel is reached the method uses a beam locator device, such as a SEM,to find the desired location at 410. At 412 the reactive material isinjected into the vacuum chamber at a controlled rate, which inconjunction with the control of the vacuum pressure and the beam energyand intensity, may determine the production rate of the chemicalradicals. The electron beam is turned on at a desired energy and beamintensity at 414, which depending upon the selected reactive materialcomposition and pressure begins the chemical etching or materialdeposition, such as chrome, of at least some portion of the samplesurface towards which the electron beam is directed. The reactionproducts are removed by the vacuum system.

At 416, the surface is examined by imaging the etch region with a SEM,and it is determined if the desired level of decoration and/or contrastof the IC and defect has been reached. An endpoint to the etching may bedirectly observable by SEM by the acquisition of an image of the defect,or the reaction products from any etching that may be done may beanalyzed by any of a variety of down stream analytic methods, such asRGA, to determine if the material being etched has a specificcomposition, such as may occur when a buried layer is reached. Otherendpoints may include the time of the etching and decoration deposition,a thickness of the top layer removed by etching, or a thickness of thedeposited layer of decoration, such as a metal thickness. The exposedsurface and the imaged particle or other defect may also be analyzed bySEM based analysis methods, such as EDAX or XES to determine theproperties of the particle. At 418, it is determined whether the currentprocessing of the IC top layer material has been etched or depositdecorated sufficiently to provide optimum defect imaging. If not, themethod returns to 412.

If the current layer contrast etching and decoration deposition has beencompleted, then it is determined at 420 if there is an additional layerthat needs to be etched, for example, to enable removal of a particle,or whether there is to be a localized etch or deposition done to fix thedefect, as may occur if a metal particle has shorted out two signal orpower lines. If not, the method ends at 430.

If there is another process to complete prior to ending the method, thena new reactive material may be injected into the vacuum chamber at 422,the electron beam is turned on to the desired energy level and intensityat 424, and the etch or deposition process result is imaged and analyzedat 426 as previously done at 416. At 428, it is determined if thepresent process has completed the etching or deposition. If not themethod returns to 422. If the additional process is completed and imagesare formed, then the method ends at 430. In this fashion, the IC defectimaged in the first portion of the exemplary process, may be repairedand returned to service or testing.

FIG. 5 is a block diagram of a general electronic device in accordancewith an embodiment of the invention with an electronic system 500 havingone or more device defects image enhanced and/or repaired according tovarious embodiments of the present invention. Electronic system 500includes a controller 502, a bus 504, and an electronic device 506,where bus 504 provides electrical conductivity between controller 502and electronic device 506. In various embodiments, controller 502 and/orelectronic device 506 include an embodiment for a portion of the devicehaving an IC die defects image enhanced and/or repaired as previouslydiscussed herein. Electronic system 500 may include, but is not limitedto, information handling devices, wireless systems, telecommunicationsystems, fiber optic systems, electro-optic systems, and computers.

FIG. 6 depicts a diagram of an embodiment of a system 600 having acontroller 602 and a memory 606. Controller 602 and/or memory 606include a portion of the circuit having IC devices and memory chips withdefects image enhanced and/or repaired in accordance with the disclosedembodiments. System 600 also includes an electronic apparatus 608, and abus 604, where bus 604 may provide electrical conductivity and datatransmission between controller 602 and electronic apparatus 608, andbetween controller 602 and memory 606. Bus 604 may include an address, adata bus, and a control bus, each independently configured. Bus 604 alsouses common conductive lines for providing address, data, and/orcontrol, the use of which may be regulated by controller 602. In anembodiment, electronic apparatus 608 includes additional memory devicesconfigured similarly to memory 606. An embodiment includes an additionalperipheral device or devices 610 coupled to bus 604. In an embodiment,controller 602 is a processor. Any of controller 602, memory 606, bus604, electronic apparatus 608, and peripheral device or devices 610 mayinclude ICs treated in accordance with the disclosed embodiments. System600 may include, but is not limited to, information handling devices,telecommunication systems, and computers. Peripheral devices 610 mayinclude displays, additional memory, or other control devices operatingwith controller 602 and/or memory 606.

CONCLUSION

A method is presented for enhancing detection of defects on or under anIC device surface by positioning the sample in a vacuum chamber, andcreating a layer of a reactive material in proximity with the surface ofthe IC. The layer of reactive material may be excited by an energeticbeam to form chemical radicals in the region surrounding the energeticbeam. The radicals may remove a portion of the surface of the structureby chemical etching until the desired amount of etching needed toimprove the contrast ratio between the defect and the sample substrateis obtained. The material removed from the surface may also be analyzedto characterize the material in various ways. With such an arrangement,the defects on an IC chip may be enhanced and made more detectable. Themethod may also be used to form localized depositions of dielectric orconductive materials as needed to improve the size or conductivity ofthe defects, which may improve the ability of a scanning electronmicroscope to image and detect the defects.

The reactive material may comprise various types of halogen in gaseous,liquid or solid form to form an etching ambient that may be eitherselective for one material over another, or may be non-selective. Thereactive material may comprise various metallo-organic or metallo-halidematerials to form a deposition ambient, which may also be eitherselective for deposition on one material and not on another, or may benon-selective and form a deposition relatively evenly over the selectedsmall spot surrounding the energetic beam. In an embodiment, thereactive material is xenon fluoride, which is a solid at standardtemperature and pressure, and sublimes in the vacuum chamber. In anembodiment, the reactive material includes chromium, which has a greaterconductivity than dielectric materials and thus helps dissipate chargebuildup in a SEM image. Chromium has a higher electron yield thandielectric layers, which increases the signal to noise ratio in a SEMimage. Chromium also decorates various defects, such as particles, byincreasing the size of the defect, making detection of small defectseasier.

The reactive material may be directed to the region near the surface ofthe IC chip by a formed jet of vapor or may simply be allowed to diffusethrough the vacuum chamber. The reactive material may be adsorbed ontothe surface of the material, or may be a gas in the vicinity of thesurface, or may condense or precipitate onto the surface. The reactivematerial may be a mixture of materials (that is chemical precursors)which react with one another, especially when activated or excited toform chemical radicals by the energetic beam, and may include a materialthat does not directly interact with the other reactive materials, butrather acts as a reaction catalyst, an inhibitor, promoter, or reactionbuffer.

The method of exciting the layer of reactive materials may use anenergetic beam such as an electron beam. The electron beam may have adiameter of less than 0.01 μ, or greater than 1.0 μ, and may typicallybe about 0.005 μ,depending upon the size of the area that is to beetched, or decorated by deposition. The electron beam may have a lowerenergy or beam intensity to slow the etch rate to improve etch controland relative etch ratios, or may be defocused to etch a wider area. Theelectron beam may be scanned to cover the desired etch area or to etch adesired shape. The etch areas may be made as small as the electron beamcan focus, plus the mean free path of the generated chemical radicals,and the etch area may have a diameter of less than 1.0 μ. The electronbeam may be part of a scanning electron microscope (SEM), and the SEMmay be used to provide an image of the process as etching occurs.

The surface material removed by the chemical radicals during thedecoration and contrast operations may be analyzed by well knownanalytical methods, including downstream analysis systems such asresidual gas analyzer (RGA), mass spectroscopy, optical emissionspectroscopy, atomic absorption spectroscopy, infrared spectroscopy, andRaman spectroscopy. The surface may be directly analyzed by variousmethods such as energy dispersive analysis of X-rays (EDAX), XES, orother SEM based analytic methods. This analysis may provide informationon the materials present on the surface, and may be used to determinethe appropriate etch environment to use in the contrast and decorationprocesses.

The optimum reactive material may be selected by choosing a chemicalradical, or combination of radicals, that preferentially etches onematerial faster than other materials, such as fluorine radicals etchsilicon oxides, and various types of glasses, at a much higher rate thanfluorine radicals etch metals or organic materials. By using a radicalmaterial or mixture having a high etch ratio for oxides over nitrides,it is possible to substantially remove a glass layer underlying anitride particle and to thus greatly increase the contrast between thetwo different dielectric materials, thereby increasing the sensitivityof the SEM image.

In an embodiment, the vacuum chamber and electron beam are a part of ascanning electron microscope (SEM), and the progress of etching anddecorating deposition may be observed by the SEM. The etching anddeposition operations may be terminated when the SEM image is optimizedfor the specific combination of materials present.

Another illustrative embodiment of the invention includes a system forlocalized chemical etching and deposition, including a vacuum chamberand a fixture for positioning a sample, a system, such as a gas inletjet, for creating a layer of a chemical reactant proximate to thesurface of the sample. An energetic beam, such as an electron beam froma SEM, is directed at the surface of the sample to form chemicalradicals in the chemical reactant, such as xenon difluoride for anetching ambient, which may etch the sample in the region around the siteof the energetic beam. The ambient may also include chromium containingcompounds for decoration depositions on the sample. Material removedduring an etching process may be analyzed to determine the compositionof various portions of the surface of the sample. Areas smaller than onemicron in diameter may be etched or deposited to increase the contrastbetween different materials, or to decorate the surface to improve andenhance defect images on the sample substrate.

An illustrative embodiment of the invention includes an apparatus forenhancing detection of surface defects, including a vacuum chamber witha fixture disposed for positioning a sample chemical radical inducedetching and radical induced deposition. There is a material inlet in thevacuum chamber for creating a layer of a selected chemical combinationin proximity with the surface of the sample, and an energetic beam, suchas an electron beam, having a selected diameter and a selected energylevel directed at a selected location on the surface of the sample. Theenergetic beam forms chemical radicals in the chemical layer near thesurface. These radicals etch the surface materials, or deposit materialson the surface. The apparatus includes an etch endpoint detector and animager for detecting surface defects.

The described embodiments are directed towards the use of an electronbeam to activate an adsorbed material forming a layer on an IC chip, andforming chemical radicals to etch the surface material of the IC, butthe disclosure is not so limited, and may he applied to other structuresand devices, such as printed circuit boards (PCBs), multi-chip modules(MCMs), liquid crystal display (LCD) devices, electronic displays,micro-electromechanical devices (MEMs), or other manufactured electronicor mechanical devices requiring failure analysis testing and materialidentification. Other means of forming local chemical radicals otherthan electron beams are included in this disclosure, to include focusedmicrowave beams, laser and maser beams, X-ray and other energeticradiation sources. The material used to form the chemical radicals maybe a gas, an evaporated liquid, a sublimed solid, or may be chemicallyformed by mixing precursor materials at the surface of the structure tobe analyzed, or mixed remotely from the surface and either passively oractively transported to the region around the surface of the IC, orother structure. The reactive material may be either adsorbed onto thesurface, precipitated onto the surface, or form a fluid layer inproximity to the surface, including a gaseous layer in the region aroundthe IC surface. The generated chemical radicals may be used toselectively etch the surface as described in the described embodiments,or may react with other provided, or already present materials, to formdielectric, conductive or other materials to become a local depositionreaction. Such depositions may be used to refill the previously etchedregion to return the IC to working condition.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement that is calculated to achieve the same purpose maybe substituted for the specific embodiments disclosed, described andshown. This application is intended to cover any adaptations orvariations of embodiments of the present invention. It is to beunderstood that the above description is intended to be illustrative,and not restrictive, and that the phraseology or terminology employedherein is for the purpose of description and not of limitation.Combinations of the above embodiments and other embodiments will beapparent to those of skill in the art upon studying the abovedescription. The scope of the present disclosure includes any otherapplications in which embodiments of the above structures andfabrication methods are used. The scope of the embodiments of thepresent invention should be determined with reference to the appendedclaims, along with the full scope of equivalents to which such claimsare entitled.

1. A method of enhancing detection of defects on a surface, comprising:positioning a surface to be examined in a vacuum chamber; creating alayer of a reactive material in proximity with the surface; exciting aportion of the layer of reactive material in proximity to the surface toform chemical radicals; removing a portion of the surface in proximityto the excited portion of the layer of reactive material; and continuingthe creating, exciting, and removing steps until at least one of aplurality of stop criteria occurs.
 2. The method of claim 1, whereinfurther after a first predetermined time period of removing a portion ofthe surface, the surface is examined for defects.
 3. The method of claim1, wherein the stop criteria include at least one of an optical image ofa defect, a scanning electron microscope image of a defect, apredetermined time has elapsed, a predetermined thickness of the surfacein proximity to the excited portion of the layer of reactive material isremoved, and at least one of a plurality of materials is detected in adownstream analysis detector.
 4. The method of claim 1, wherein anenergetic beam excites the portion of the layer of reactive material inproximity to the surface.
 5. The method of claim 4, wherein theenergetic beam includes one of an electron beam, an ion beam, a laserbeam, a maser beam, a microwave beam, and an X-ray beam.
 6. The methodof claim 1, wherein the surface includes an integrated circuit.
 7. Themethod of claim 1, wherein the method includes removing a portion of afirst material layer, and the surface includes an exposed portion of asecond material layer below the first material layer.
 8. The method ofclaim 7, wherein the removing a portion of the first material layerincludes etching the entire thickness of at least one dielectric layer.9. The method of claim 8, wherein the removing a portion of the firstmaterial layer includes stopping the etching at a surface of aconductive material layer.
 10. The method of claim 8, wherein theremoving a portion of the first material layer includes stopping theetching at a surface of a second dielectric material layer havingdifferent properties from the first material layer.
 11. The method ofclaim 3, wherein a scanning electron microscope is used to provide thevacuum chamber and the electron beam, and the surface is imaged duringthe etching cycle to determine when a stopping criterion of the bestimage contrast of the defect is obtained in the scanning electronmicroscope.
 12. The method of claim 1, wherein the reactive materialcomprises a halogen.
 13. The method of claim 1, wherein the reactivematerial is a gas.
 14. The method of claim 12, wherein the reactivematerial is xenon fluoride.
 15. The method of claim 1, wherein an areacontaining the chemical radicals has a diameter of less than 1.0 μ. 16.The method of claim 3, wherein the downstream analysis detector includesat least one of residual gas analysis, mass spectroscopy, opticalemission spectroscopy, atomic absorption spectroscopy, infraredspectroscopy and Raman spectroscopy.
 17. The method of claim 1, whereina vacuum pressure of the vacuum chamber is determined by a desired meanfree path of the chemical radicals generated by the exciting the layerof reactive material in proximity to the surface.
 18. A method ofenhancing detection of defects on a surface, comprising: positioning asurface to be examined in a vacuum chamber; creating a layer of areactive material in proximity with the surface; exciting a portion ofthe layer of reactive material in proximity to the surface to formchemical radicals; depositing a material layer upon a portion of thesurface in proximity to the excited portion of the layer of reactivematerial; and continuing the creating, exciting, and depositing stepsuntil at least one of a plurality of stop criteria occurs.
 19. Themethod of claim 18, wherein further after a first predetermined timeperiod of depositing a material layer on a portion of the surface, thesurface is examined for defects.
 20. The method of claim 18, wherein thestop criteria include at least one of an optical image of a defect, ascanning electron microscope image of a defect, a predetermined time haselapsed, and a predetermined thickness of the deposited material layeris reached.
 21. The method of claim 18, wherein an energetic beamexcites the portion of the layer of reactive material in proximity tothe surface.
 22. The method of claim 21, wherein the energetic beamincludes one of an electron beam, an ion beam, a laser beam, a microwavebeam, and an X-ray beam.
 23. The method of claim 18, wherein the surfaceincludes an integrated circuit.
 24. The method of claim 18, wherein themethod includes removing a portion of a first material layer, and thesurface includes an exposed portion of a second material layer below thefirst material layer.
 25. The method of claim 21, wherein a scanningelectron microscope is used to provide the vacuum chamber and theelectron beam, and the surface is imaged during the depositing cycle todetermine when a stopping criterion of the best image contrast of thedefect is obtained in the scanning electron microscope.
 26. The methodof claim 18, wherein the reactive material comprises a metallo-halidecompound.
 27. The method of claim 26, wherein the reactive material is agas.
 28. The method of claim 26, wherein the reactive material comprisesa halogen, a silicon containing material, an oxidizer, ametallo-organic, a metallo-halide, and a chemically inert material. 29.The method of claim 18, wherein an area containing the chemical radicalshas a diameter of less than 1.0 μ.
 30. The method of claim 18, wherein avacuum pressure of the vacuum chamber is determined by a desired meanfree path of the chemical radicals generated b-y the exciting the layerof reactive material in proximity to the surface.